1. Field of the Invention
The present invention relates to an inkjet printer, and, more particularly, to an ejection controlling device for an inkjet printer, and a controlling method thereof, that is capable of adjusting an amount of ejected ink properly.
2. Description of the Related Art
A general inkjet printer drives an ink ejection heater for ejecting ink in an ink cartridge to print onto a printing medium. The inkjet printer comprises a heater driving control unit for controlling a width or waveform of a driving pulse to drive the ink ejection heater according to a temperature of an ink cartridge head.
FIG. 1 is a graph showing a driving pulse of a conventional ink injection heater. P1 represents a pre-heat pulse for pre-heat, P3 represents a main pulse of the heater, and P2 is an interval between P1 and the main pulse P3.
Conventionally, the temperature of the ink cartridge head is measured so that the width of the driving pulse is changed according to the measured temperature, to adjust a possible time for ejection. Namely, when the measured temperature is lower than a predetermined temperature, the pre-heat pulse P1 is added, or the width of the main pulse is lengthened, to increase an amount of energy applied to the heater. Further, when the measured temperature is higher than the predetermined temperature, the pre-heat pulse is removed, or the width of the main pulse is shortened, to decrease the amount of energy applied to the heater, thereby obtaining a uniform ink ejection feature.
With the above conventional method for adjusting the pulse applied to the ink ejection heater according to the temperature of the ink cartridge head, the same pulses are applied to all heads, according to the temperatures of the heads, without distinction as to whether the heads are of a mono cartridge or a color cartridge. However, there are variations according to the heads, and resistances of the ink ejection heater in a predetermined range, which function as important factors in determining the amount of ink ejection energy. These variations prevent a uniform amount of ink ejection, thereby degrading the printing quality.